Phenol formates

ABSTRACT

WHEREIN R, m and t-Bu are as defined above with (A) a formamide derivative and a chloride or (B) formic acid in the presence of an esterification catalyst. The phenol formates are superior antidegradants and stabilizers.   WHEREIN R is a straight or branched alkyl, m is O to 3 and t-Bu is tert-butyl. Such phenol formates are prepared by reacting an alkyl phenol of the formula   New phenol formates of the formula

United States Patent [72] Inventors [21 1 Appl. No. [22] Filed [45 Patented 73 Assignee [54] PI-IENOL FORMATES 5 Claims, No Drawings [52] US. Cl. 260/479 R, 252/404, 260/45.85 [5i 1 Int. Cl C07c 69/06 [50] Field of Search 260/479 [56] References Cited OTHER REFERENCES Muramatsu et al., J. Chem Soc., Japan, Pure Chem. Sect., Vol. 86 (Jan., 1965 pages A7 and H3.

Sofuku et al., Bull. Chem. Soc., Japan, Vol. 40 (1967) 292942- 2943.

Olam, Friedel-Crafts and Related Reactions, Vol. 1]] part 2, Wiley & Sons, New York 1964) pp. 1211, 1212, 1227 Morokuma et al., Bull. Chem. Soc., Japan 36(5) pp. 541- 546(1963) Chem. Abst., Vol. 48, 9722f, citing Yoshikawa et a1. (1954) Chem. AbsL, Vol. 54, 3640, citing lsaguhiants et al. l96 0) Chem. Abst., Vol. 54, 1263!), citing Br. Patent 827,632 (1960) Wagner et al., Synthetic Org. Chem. Wiley & Sons, New York 1953) pp- 480 481 Van Es et al., Recueil des Travaux Chim., Vol. 84, No. 9- l0 (available to public Nov. 2, 1965) Primary Examiner-James A. Patten Assistant Examiner-Vivian Garner Attorney-McGlew and Toren ABSTRACT: New phenol formates of the formula O-CHO wherein R is a straight or branched alkyl, m is O to 3 and t-Bu is tert-butyl. Such phenol forrnates are prepared by reacting an alkyl phenol of the formula wherein R, m and t-Bu are as defined above with (A) a formamide derivative and a chloride or (B) fonnic acid in the presence of an esterification catalyst. The phenol formates are superior antidegradants and stabilizers.

PHENOL FORMATES This invention relates to novel phenol formates and a novel process for preparing the same. More particularly, it relates to a new class of the alkylphenol formates having the formula t-B l1 wherein R represents a straight or branched alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert.-butyl, npentyl, n-hexyl, n-heptyl or tert.-octyl, m is an integer of to 3 inclusive and, where m is an integer of 2 to 3, R's may be the same or difierent and t-Bu represents tert-butyl group and a novel process for preparing the same.

The alkylphenol fonnates of the above-mentioned fon-nula (l) are novel compounds unknown in the prior art.

They have been found to be highly active antidegradants or stabilizers for various organic materials including fats and oils, natural and synthetic rubbers and other polymeric materials.

it has also been found that the alkyl phenol fonnates of the above-mentioned formula (I) can be prepared by a novel process characterized in that the alkyl phenol having the formula wherein R, m and t-Bu have the same meanings as set forth above is subjected to Vilsmeier reaction or to the reaction with formic acid in the presence of an esterification catalyst.

Accordingly, it is an object of this invention to provide novel alkyl phenol fonnates of the above-mentioned formula (I which are useful as an antidegradant.

Another object of this invention is to provide a novel process for the preparation of the alkyl phenol formates of the above-mentioned formula (I).

Other objects will be apparent from the following detailed description.

In carrying out the process of this invention, one embodiment of the present process is in that the alkyl phenol of the above-mentioned formula (ll) is subjected to Vilsmeier reaction. In this reaction, there may be employed any of various Vilsmeier reagents which are known by those skilled in the art, that is, any combination of a formamide derivative and a chloride.

Suitable examples of the chloride to be employed include phosphorus oxychloride, phosgene, thionyl chloride and phosphorus pentachloride. Examples of the formamide derivatives to be employed include dimethyl fonnamide, diethyl formamide, methylformamide and methylphenylformamide, but dimethylformamide is most preferable because of commercial availability. The reaction temperature is generally in the range of about 70l00 C. and most preferably the reaction is conducted at about 80 C. The reaction period will mainly depend upon the kind and amount of the starting material employed as well as the reaction temperature applied, but in general the reaction is completed from approximately 5-1 5 hours.

Any other solvent will not be required in this reaction since the fonnamide derivative will act as both a reagent and a solvent by employing it in an excess over the stoichiometrically required amount.

After completion of the reaction, the reaction product may be easily recovered and purified by a conventional means.

Another embodiment of the present process is the reaction of the alkyl phenol of the above-mentioned formula (II) with fonnic acid in the presence of an esterification catalyst to form the formate of this invention. In this reaction, there may be conveniently employed any catalyst which is commonly known as an esterification catalyst in the art. Typical examples of these catalysts which may be employed in this invention include polyphosphoric acid alkyl esters, p-toluenesulfonic acid, phosphorus oxychloride and polyphosphoric acid. Requirement for the solvent and the reaction temperature and period may be optionally selected and determined by those skilled in the art, based upon the catalyst employed. For instance, where polyphosphoric acid alkyl esters are employed, the reaction is generally conducted in the absence of a solvent at room temperature for about 5-15 hours, and, where p-toluenesulfonic acid is employed, the reaction is generally conducted in the presence of a suitable solvent such as benzene, ligroin, petroleum benzine and the like at about 70l 00 C. for about 10-20 hours. After completion of the reaction, the reaction product may be easily l0 recovered and purified by a conventional means.

Representative of the alkyl phenol fonnates which can be prepared by the process of this invention are the following;

4-methyl-6-tert.-butyl phenol formate,

3-methyl-6-tert.-butyl phenol formate,

3-methyl-4,6-di-tert.-butyl phenol fonnate,

2,4-di-tert.-butyl-5-methyl phenol fonnate,

3,4-dimethyl-6-terL-butyl phenol formate,

2-methyl-4-tert.-butyl phenol formate,

4-ethyl-6-tert.-butyl phenol formate,

3-ethyl-6-tert.-butyl phenol formate,

3-tert.-octyl-6-tert.-butyl phenol formate,

2,4-di-tert.-butyl phenol fonnate.

The following examples serve to illustrate this invention without intending to limit it thereto.

EXAMPLE 1 Preparation of 3-methyl-6-tert.-butylphenol formate To a cooled solution of 20 g. of phosphorus oxychloride in 20 ml. of dimethylformamide were added 20 g. of 3-methyl-6- tert.-butylphenol while maintaining the temperature at 5-20 C. with ice-cooling. The reaction was carried out at C. for 10 hours. After completion of the reaction, the reaction mixture was poured into ice-water, the resulting mixture neutralized with aqueous sodium acetate and extracted several times with petroleum-ether. The combined extracts were washed successively with aqueous sodium carbonate and water, dried over anhydrous sodium sulfate and distilled in vacuum, thereby yielding 16.9 g. of the desired product, boiling at 9294 C./4.5 mml-lg.

Yield: 84.5 percent Analysis:

Calculated for C,,H,,O,:

Found:

C, 74.l9; H, 9.34 C, 74.40; H, 9.58.

Infrared spectrum (liquid film): 1743 cm."(ester; vC.=0), 1187 cm."(formic acid ester;

vc.=0N.M.R spectrum (CC1 Absorption band of proton of benzene ring with an intensity of 3H at o=2.8-3.7.

EXAMPLE 2 Preparation of 4-methyl-6-tert.-butylphenol formate Calculated for C,,H 0,:

Found:

C, 7419; H, 9.34. C, 74.37; H, 9.48.

Infrared spectrum (liquid film):

Calculated for C,.H O,1

Found:

C, 77.37; H, 9.74. C, 77. I; H, 9.57.

Infrared spectrum (nujol): 1752 cm.(ester: vc.=0), I185 cm."(formic acid ester:

vc.=O).

EXAMPLE 4 Preparation of 4-tert.-octyl-6-tert.-butyl phenol formate To a solution obtained by dropwise-addition of 10 g. of phosphorus oxychloride to 20 ml. of dimethylformamide with stirring and ice-cooling were added 9 g. of 4-tert.-octyl-6-tert.- butyl phenol. The resulting mixture was heated with stirring at 85 C. for 32 hours. After completion of the reaction, the reaction mixture was poured into ice-water, the resulting mixture neutralized with aqueous sodium carbonate and extracted several times with benzene. The combined extracts were washed successively with aqueous sodium carbonate and water, dried over anhydrous sodium sulfate and then distilled in vacuum, thereby yielding 7.2 g. of the desired product, boiling at l l5-l 17 C./2.5 mmHg.

Yield: 72.0 percent.

Analysis:

Calculated for C,,l-l,,0,:

Found:

C. 78.57; H. lO.4l. C. 78.92; H. l0.60.

Infrared spectrum (liquid film): I745 cm."(ester; vc.=O), ll90 cm."(formic acid ester:

vc.=O).

EXAMPLE 5 Preparation of 2,4-di-tert.-butylphenol formate C. 76.88; H. 9.46. C, 77.06; H, 9.62

Calculated for C,,H,,O,:

Found.

Infrared spectrum (liquid film): I750 cm.(ester: vc.=0), H9O cm. (formic acid ester:

vc.==O).

EXAMPLE 6 Preparation of 3-methyl-6-tert.-butylphenol formate A mixture of 10 g. of 3-methyl-6-tert.-butyl phenol, 5 g. of 98 percent formic acid and 50 g. of polyphosphoric acid ethyl ester was stirred at room temperature for 8 hours and then allowed to stand at that temperature overnight. Thereafter, the reaction mixture was poured into ice-water and extracted several times with benzene. The combined extracts were washed successively with water, a 5 percent aqueous sodium carbonate solution and again water, dried over anhydrous sodium sulfate and then distilled in vacuum, thereby yielding 7.5 g. of the desired product as colorless oils, boiling at -9 I C./3 mmHg. Yield: 64.2 percent.

Analysis:

Calculated for C I-I O Found:

C. 74.l9; H, 9.34. C, 74.42; H, 9.53.

Infrared spectrum (liquid film): 1743 cm. (ester: vc.=0), 1187 cm. (formic acid ester:

EXAMPLE 7 Preparation of 4-methyl-6-tert.-butylphenol formate A solution of 50 g. of 4-methyl6-tert.-butyl phenol, 30 g. of 98 percent formic acid and 2.0 g. of p-toluenesulfonic acid in 200 ml. of benzene was heated under reflux for 15 hours. After completion of the reaction, the reaction mixture was washed successively with water, a 5 percent aqueous sodium carbonate solution and again water, dried over anhydrous sodium sulfate and then distilled under reduced pressure, thereby yielding 43.1 g. of the desired product as colorless oils, boiling at 86-88 C./4 mmHg.

Analysis:

C, 7419; H. 9.34. C, 74.48; H, 9.59.

Calculated for C H,,O,:

Found:

EXAMPLE 8 Preparation of 2,4-di-tert.-butyl-5-methylphenol formate A mixture of IO g. of 2,4-di-tert.-butyl-5-methyl phenol, 10 g. of 98 percent formic acid and 10 g. of phosphorus oxychloride was heated at a temperature of 70-80 C. for 6 hours. After completion of the reaction, the reaction mixture was poured into ice-water and the resulting mixture was extracted several times with benzene. The combined extracts were washed successively with water, a 5 percent aqueous sodium carbonate solution and again water, dried over anhydrous sodium sulfate and the solvent was distilled off. The residue thus obtained was recrystallized from ethanol to give 5.6 g. of the desired product as white crystals, melting at 7879 C.

Yield: 49.9 percent Analysis:

C, 77.37: H, 9.74. C, 77.52; H, 9.88.

Calculated for C, H,.O,1

Found: 

2. 4-Methyl-6-tert.-butyl phenol formate.
 3. 2,4-Di-tert.-butyl-5-methyl phenol formate.
 4. 4-tert.-Octyl-6-tert.-butyl phenol formate.
 5. 2,4-Di-tert.-butyl phenol Formate. 